A touchscreen display is a user interface commonly used in recent handheld devices, for example, a cellular phone, a personal digital assistant (PDA), a smartphone, a portable multimedia player (PMP), a tablet computer, a digital camera, and the like. Interactions on a touchscreen handheld device are typically confined to x and y coordinates on the touchscreen display. While additional interaction in the z-plane may be added to measure touch force, a major limitation in interacting with such handheld devices still exists because two-handed operation is generally required (i.e., holding the device with one hand while interacting with the other hand). Thus, it may be difficult to execute two-handed operations, which are often needed when a user attempts to select small targets, or when fine dynamic motor movement is required for target manipulation on the screen.